The present invention relates in general to the rotor design for a fluid centrifuge that is constructed and arranged to separate undesired particulate matter out of a fluid. Typical of such fluid centrifuge designs is the use of an outer centrifuge housing or shell that defines a hollow interior. A rotor is positioned within the hollow interior and is constructed and arranged to rotate at a high (RPM) rate relative to the centrifuge housing. Various arrangements of bearings, bushings, shafts, and shaft spuds have been used to enable this relative rotary spinning of the rotor within the centrifuge housing. One design variation for centrifuge rotors of the type being discussed herein is to use the exiting fluid for driving the rotor (i.e., self-driven) via one or more tangential nozzles.
Positioned within the rotor is a particulate separating subassembly that is constructed and arranged to improve the separating efficiency of the rotor. Over the years, a number of designs have been tried to perform the particulate separating function. One particulate separating subassembly design used by Fleetguard, Inc. of Nashville, Tenn., is a stack of closely spaced cones identified by their “ConeStac” trademark and disclosed in various U.S. patents, such as U.S. Pat. No. 5,575,912, issued Nov. 19, 1996 to Herman, et al.; U.S. Pat. No. 5,637,217, issued Jun. 10, 1997 to Herman et al.; and U.S. Pat. No. 6,017,300, issued Jan. 25, 2000 to Herman.
Another particulate separating subassembly design used by Fleetguard, Inc. is a spiral vane that includes a series of curved (spiral) vanes radiating from a central hub. The spiral vanes rotate as part of and with the rotor assembly at a high (RPM) rate. The centrifugal forces exerted on the heavier particulate cause this particulate to separate out from the fluid being processed by the centrifuge. Spiral vane designs are disclosed in various U.S. patents, such as U.S. Pat. No. 6,551,230, issued Apr. 22, 2003 to Herman et al.
Whether considering a cone stack design or a spiral vane design, typically there is a baseplate as part of the rotor assembly and an interface between the particulate separating subassembly and the baseplate that needs to be sealed. If leakage through this interface is allowed to occur, then collected particulate matter (i.e., soot or sludge) is washed out of the rotor and re-entrained into the fluid being processed. This means reduced efficiency and a consequence that is regarded as detrimental.
If this interface between the particulate separating subassembly and the baseplate can be effectively sealed to eliminate any risk of leakage, it would constitute a rotor design improvement. The present invention addresses this design challenge by creating a unitary combination of the particulate separating subassembly and the baseplate. By molding or casting these two portions into a one-piece, unitary component, there is no interface to be sealed and no risk of leakage at that interface. The fabrication of a single component, as compared to two components (spiral vane and baseplate) that have to be assembled, represents a cost savings and in the case of the present invention, a savings in terms of cleaning and servicing. The present invention thus results in an improved part configuration in terms of rotor efficiency and an improved part configuration in terms of cost. Other design features are disclosed as part of the present invention that add improvements and value to the structure.
In non-disposable (take-apart, cleanable) rotor designs, the user has to clean the internal components of the rotor and separate the collected contaminant from those components. This process is time consuming and typically requires a chemical wash station. The present invention allows the user to quickly and easily remove the “capsule” containing the contaminant, which saves time and cost, eliminates the need for parts washing, and is a clean process (i.e., the contaminant is contained).